University Of Pune Question Paper
S.E. (Elex. and E & TC) (Semester – II) Examination, 2011
ANALOG COMMUNICATION
(2003 Course)
Time : 3 Hours Max. Marks : 100
Instructions : 1) Answer any 3 questions from each Section.
2) Answers to the two Sections should be written in separate
books.
3) Neat diagrams must be drawn wherever necessary.
4) Black figures to the right indicate full marks.
5) Use of logarithmic tables, slide rule, Mollier charts, electronic
pocket calculator and steam tables is allowed.
6) Assume suitable data, if necessary.
SECTION – I
1. a) Enlist and explain basic types of modulation techniques. 8
b) What is baseband signal ? State different types of baseband signals with
their range of frequencies. 6
c) Compare TDM and FDM. 4
OR
2. a) State various types of communication channels with their bandwidth. Also
state application of each. 8
b) Compare PAM, PWM and PPM. 6
b) Explain basic block diagram of a communication system. 4
3. a) Explain high level AM transmitter. 8
b) Modulating frequencies of 5KHz and 6 KHz are applied to SSB modulator
using a carrier frequency of 150 KHz.
1) Sketch the spectrum of output of SSB modulator if the filter method of
SSB generation passes the USB.
2) Sketch the output if it passes LSB.
3) Sketch the spectrum of modulating signal. 8
OR
[3962] – 310 -2-
4. a) Explain any one balanced modulator circuit in detail. 8
b) An AM transmitter has carrier of 100 kW power and modulated by a
modulation index of 75%. Find total power transmitted by the transmitter
in the following cases :
1) DSBFC 2) DSBSC 3) SSB 8
5. a) Explain FM generation by Armstrong method. 8
b) An angle modulated signal given by
V (t) 10 cos (2 10 20 sin 2000 t) 6
FM = π × + π
Find :
i) Power of modulated signal
ii) Deviation
iii) Bandwidth. 8
OR
6. a) Explain FM generation by reactance modulator. 8
b) Compare :
i) AM and FM
ii) NBFM and WBFM 8
SECTION – II
7. a) What is tracking ? Explain two-point and three-point tracking. 8
b) Explain radio receiver characteristics. 6
c) A superhet receiver is tuned to 455 KHz. Its local oscillator provides mixer
with an input of 1045 KHz. Calculate image frequency. 4
OR
8. a) Explain superheterodyne receiver in detail. 10
b) Draw and explain practical diode detector. 8
-3- [3962] – 310
9. a) Explain internal and external sources of noise. 8
b) Three amplifiers have the following characteristics :
F1
= 9 dB G1 = 45 dB
F2
= 6 dB G2 = 35 dB
F3
= 4 dB G3 = 15 dB
The amplifiers are connected in tandem. Determine the overall noise figure
and equivalent noise temperature. 8
OR
10. a) Explain performance of DSBSC in presence of noise. 8
b) Explain the terms :
i) Noise figure ii) Noise temperature
iii) Noise bandwidth iv) Signal to noise ratio. 8
11. a) State different types of propagation and explain them. 8
b) Draw and explain Yagi Uda antenna. State its application. 8
OR
12. a) Explain half wave dipole antenna. 6
b) Explain fading with its causes. 6
c) Define : 4
1) Virtual height 2) Skip distance.
————————
B/
S.E. (Elex. and E & TC) (Semester – II) Examination, 2011
ANALOG COMMUNICATION
(2003 Course)
Time : 3 Hours Max. Marks : 100
Instructions : 1) Answer any 3 questions from each Section.
2) Answers to the two Sections should be written in separate
books.
3) Neat diagrams must be drawn wherever necessary.
4) Black figures to the right indicate full marks.
5) Use of logarithmic tables, slide rule, Mollier charts, electronic
pocket calculator and steam tables is allowed.
6) Assume suitable data, if necessary.
SECTION – I
1. a) Enlist and explain basic types of modulation techniques. 8
b) What is baseband signal ? State different types of baseband signals with
their range of frequencies. 6
c) Compare TDM and FDM. 4
OR
2. a) State various types of communication channels with their bandwidth. Also
state application of each. 8
b) Compare PAM, PWM and PPM. 6
b) Explain basic block diagram of a communication system. 4
3. a) Explain high level AM transmitter. 8
b) Modulating frequencies of 5KHz and 6 KHz are applied to SSB modulator
using a carrier frequency of 150 KHz.
1) Sketch the spectrum of output of SSB modulator if the filter method of
SSB generation passes the USB.
2) Sketch the output if it passes LSB.
3) Sketch the spectrum of modulating signal. 8
OR
[3962] – 310 -2-
4. a) Explain any one balanced modulator circuit in detail. 8
b) An AM transmitter has carrier of 100 kW power and modulated by a
modulation index of 75%. Find total power transmitted by the transmitter
in the following cases :
1) DSBFC 2) DSBSC 3) SSB 8
5. a) Explain FM generation by Armstrong method. 8
b) An angle modulated signal given by
V (t) 10 cos (2 10 20 sin 2000 t) 6
FM = π × + π
Find :
i) Power of modulated signal
ii) Deviation
iii) Bandwidth. 8
OR
6. a) Explain FM generation by reactance modulator. 8
b) Compare :
i) AM and FM
ii) NBFM and WBFM 8
SECTION – II
7. a) What is tracking ? Explain two-point and three-point tracking. 8
b) Explain radio receiver characteristics. 6
c) A superhet receiver is tuned to 455 KHz. Its local oscillator provides mixer
with an input of 1045 KHz. Calculate image frequency. 4
OR
8. a) Explain superheterodyne receiver in detail. 10
b) Draw and explain practical diode detector. 8
-3- [3962] – 310
9. a) Explain internal and external sources of noise. 8
b) Three amplifiers have the following characteristics :
F1
= 9 dB G1 = 45 dB
F2
= 6 dB G2 = 35 dB
F3
= 4 dB G3 = 15 dB
The amplifiers are connected in tandem. Determine the overall noise figure
and equivalent noise temperature. 8
OR
10. a) Explain performance of DSBSC in presence of noise. 8
b) Explain the terms :
i) Noise figure ii) Noise temperature
iii) Noise bandwidth iv) Signal to noise ratio. 8
11. a) State different types of propagation and explain them. 8
b) Draw and explain Yagi Uda antenna. State its application. 8
OR
12. a) Explain half wave dipole antenna. 6
b) Explain fading with its causes. 6
c) Define : 4
1) Virtual height 2) Skip distance.
————————
B/
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